American Crossroads is launching a digital ad titled "Hillary's Wall."
Saturday night's debate averaged 13.51 million viewers, CBS said.
Patrice Taylor wrote that the process is "open and inclusive."
"It is abundantly clear that Donald Trump is not a conservative," Cruz said.
"Had bin Laden been taken out, it is doubtful that 9/11 would have happened."
Thirty-two percent picked the Florida senator in an overnight poll.
Trump said South Carolina voters "understand that the war in Iraq is a disaster."
Kasich called the debates “ridiculous,” saying they are “not a way to pick a president.”
A new online CBS News poll shows Clinton leading by 19 points.
Sen. Ted Cruz is in second place in the Palmetto State.